Control mechanism for gear-driven superchargers



Nov. 30, 1926.

. 1,608,778 p, DUNWOODIE CONTROL MECHANISM FOR GEAR DRIVEN SUPERCHARGERSFiled August v, 1925 Patented Nov. 30, 1926.

- UNITED STATE-S 1,608,778 PATENT OFFICE.

DAVID DUN'WOODIII, OI DAYTON, OHIO.

common manners! son ema-narvmr sornnonaaonas.

I Application filed August 7, H23. Serial Io. 856,281.

. This invention relates to power transmission systems and its object isto provide a device of this character which will allow a driven memberto run free from sudden shocks caused by quick acceleration or.deceleration in the speed of the driving memher. A second object istoprovide a fluid pressure controlling mechanism automaticall governingthe fluid pressure in accor ancewith the speed. A further object is toprovide a fluid ressure responsive clutch member adapted toautomatically connect or disconnect the driving and driven members ofthe clutch in accordance with the acceleration or deceleration of thespeed of the driving member. A further object is to provide a geardriven supercharger of the type used for the supercharging of enginesfor high altitude o eration 1n aircraft, with an automatic'al y operatedfluid pressure system of this type. A further object is to rovide meansfor automatically applyin t e power in a gradual manner and wit outshock after the rotating parts assume a steady rotation.

With the foregoing and other objects in view, the invention consists ofthe combination of parts and in the details of construction more fullyset forth in the attached specification and claims, the specificembodiment thereof being illustrated 1n the accompanying drawings, inwhich:

Figure'l is a vertical longitudinal section through an impeller blade ofa supercharger and shows the application of the control mechanismassembly thereto.

Figure 2 is a view in section, of the presor governor, taken along line22 of Fi ure 1.

Referring more in etail to the drawings, 1 represents a pipe which isadapted to convey, to the hollow shaft 2, some suitable fluid such asoil under a pressure regulated by the speed of the engine. The hollowshaft 2 is rotatably mounted in the casing 18 in the bearings 15 and. 19provided with bushings 15' and 19' respectively. Intermediate of the twobearings and integral with the shaft 2 is arranged a gear 14 adapted tobe driven by the engine.

A supercharger impeller blade 5 is provided with a rotatable shaft 21having a collar 22 with a ball and race bearing assembly' 17. Integralwith the other end of shaft 21 is a cup-shaped extension 4'. A ball andrace assembly 16 is arranged be- 2. A collar 3' is attached tween themember 4 and the casin 18 to allow rotation of the member 4'. collar 4is mounted on the shaft-2 and has screw threadedengagement with themember 4'.

Intermediate of the members 4 and 4 is 'on. A flexible bellows 20.preferably of metallic corrugated type of'a circular cross sectlonsurrounds the end. of the shaft 2 and is arranged between and fixed tothe members 3, 3' by means of fluid tight joints. Plates 8, 8' arearranged between the membets 3 and 4 and 3 and 4' respectively, plate 8being rigidly connected to the member 3 and plate 8' being rigidlyconnected to the .plate 3' so that a fluid pressure 0 erated metalbellows is provided at the en ofthe shaft 2, formin a clutch assembly bymeans of which t e shaft 2 is interconnected to the impeller. A

The opposite end of the hollow shaft 2 is closed by means of the screwplug 10. The shaft 2 is further provided wlth an inertia member 6consisting of outer wei hted portions revolvabl mounted upon t e shaft 2so as to provi e communicating passages 7 and 13 to allow the fluidpressure to travel from the hollow shaft into the end portion 23 of thecasing 18, when the passage 7 is open. Referring more in detail to Fig.2, the weighted inertia member 6 is maintained in its normal positionupon the shaft 2 by means of a plurality of leaf springs 12. When inthis position the fluid under pressure within the center of the shaft 2has no means of exit through the passage 7, as the end of this passageis closed by the snugly fitting inside portions of the lnertia member.The fluid under pressure within the shaft 2 therefore,' forces the platefaces 8 and 8 into an en agement with the members 4 and 4' of the drivenmember.

Upon a sudden increase or decrease in the speed of the engine, theinertia of the memher 6 causes a relative movement of the shaft 2 andthis member 6, the inertia member lagging behind when the speed'of theshaft 2 is suddenly increased, so that the force of the sprin members 12is overcome momentarily an the passage? is allowed to commumcate withthe passage 13 so that the fluid may be released into the end casing 23from whence it may be led back to the main fluid supply.

Itwill be understood that the flu1d under pressure is supplied throughthe tube 1 to the main hollow shaft 2 through a suitable opening, asshown, communicating W1th the center of this'shaft; and thence to thepressure operated clutch. The expansion of the bellows forces the plates8, 8 to engage the plates 4, 4 on the driven member so that the shaft 21and the friction plates thereon are driven by the shaft 2. Upon releaseof pressure of the fluid in shaft 2 by the actuation of the inertiamember, the bellows is con-- tracted so as to assume its original normalposition and the clutch becomes inoperative and allows shaft 2 and shaft21 to rotate inde endently of each other.

@Vhen there is a sudden burst of power in starting the engine, the mainshaft 2 rotates slightly ahead of member 6. If the source inf pressurenow has had tune to bulld up a pressure within the system lead ng to theipe 1 this pressure will be released immeiiiately to the passages 7 and13. As soon as the engine begins to run at a steady uniform speed theWeights 6 resume their normal 'cen: tral position on the shaft and closethe openings 7. The pressure then starts building upiin theshaftbwhenthe clutch expands and forces the mem ers 8 and 8' against the members4, 4' forming an automatically operated clutch to drive the superchargerimpeller 5.

Should the throttle of the engine be thrown fully open, the high peak ofpower is instantaneous but not quick enough to simultaneously reach anddrive the impeller 5, because of the fact that the weights 6, beingequally sensitive, are meanwhile opening the pressure release passages7. This action, as will be clearly seen, allows flow of the fluid in theend casing 23, lessens the pressure in the bellows 20, causes adisengagement of the shafts 2 and 21 by release of the clutchtherebetween, and allows the impeller to run free. Consequently it isimpossible in the present device to transmit sudden shocks to thesupercharger impeller through a sudden change in the speed of theengine.

A sudden deceleration of the engine affects the clutch assembly in thesame manner as the sudden acceleration described, the only difference ofeffect on the control mechanism, as a whole, being that in the case ofdeceleration the inertia weights 6 fly in the opposite direction to thatin the case of acceleration.

The remainder of the action is similar in every respect.

I claim:

1. In a power transmission, in combination, a driving member and adriven member in alignment therewith. a fluid pressure responsive clutchadapted to operatively connect said members, comprising a disk rigidlyattached directly to one of said members, a

flexible metal bellows attached to the periphery of said disk, a seconddisk splined directly to said one member and attachedto said bellows, apassage for fluid pressure from said bellows to said one member, and aflat plate on each side of said bellows'and attached to the other ofsaid members and adapted to be engaged directly by the faces of saiddisks.

2. In a device of the character described, a driving shaft adapted to bedriven by a power plant, a driven member, a source-of fluid pressureincident to the operation of said power plant, a fluid ressure operatedclutch operatively connecting said driving shaft to said driven memberand control means adapted to control the operation of said clutchagainst sudden changes in the speed of said driving shaft including avalve for the fluid operated clutch, and a'speed control inertia membermounted on said driving shaft for controlling said valve.

3. In a device of the character described, a driving shaft adapted to bedriven b a power plant, a driven member, a source of fluid pressureincident to the operation of said power plant, a fluid pressure 0 eratedclutch operatively connecting said riving shaft to said driven member,and control means therefor including resiliently seated valves and speedcontrolled inertia members for seating and unseating said valves.

4. In a device of the character described, in combination, a hollowdriving shaft adapted to be driven by a power plant, a driven member, asource of fluid pressure adapted to communicate with the interior ofsaid driving shaft, a pressure responsive clutch member mounted on saidshaft and adapted to operatively connect said shaft to said drivenmember, and an inertia operated control means mounted on said shaft andadapted to control the fluid pressure at the interior of the drivingshaft.

5. In a device of the character described, in combination. a hollowdriving shaft adapted to be driven by a power plant, a driven member, asource of fluid pressure adapted to communicate with the interior ofsaid driving shaft, a pressure responsive clutch member mounted on saidshaft and adapted to operatively connect said shaft to said drivenmember, control means mounted on said, shaft and adapted tocommunicatewith the interior thereof, said control means embodyingpressure varying means operated by changes in the speed of rotation ofsaid driving shaft.

6. In a power transmission system, in combination, a driving member, adriven memher. a pressure responsive clutch adapted to operativelyconnect said driving member to said driven member. and automatic controlmeans for said clutchincluding valve means and inertia operated controlmeans mounted on one of said members for controlling the valve means.

7. In a control mechanism of the character described, a drive shaftoperable at variable speeds, a driven member operated thereby coaxiallyarranged with respect thereto, and means providing an automatiwith abore, exten call detachable driving connection between sai drive shaftand said driven member comprising an expansible ipressure fluid clutch,having the expansible member thereof enclosing the end of said drivingshaft for communicating with a bore, extending longitudinally of saidshaft through which pressure uid is introduced to sald clutch, a drivingplate rigid on said shaft and connected with one end of said expansiblemember, a second driving plate capable of movement longitudinallyrelative to said shaft and adapted to en age said driven member andconnected on t e other end of said expansible member.

8. In a control mechanism of the character described, a drive shaftoperable at variable coaxially arranged with respect thereto, and meansproviding an automatically detachable driving connection between saiddrive shaft and said driven member, com rising an expansible pressurefluid clutch aving the expansible member thereof enclosing the end ofsaid driving shaft for communioatin ing longitudinally of sai shaftthrough which pressure fluid is introduced to said clutch, a drivingplate rigid on saidshaft and connected with one end of said expansiblemember, a second driving plate capable of movement lon itudinallyrelative to said shaft and adapte to engage and frictionally drive saiddriven member and connected on. the other end of said expansible member,and means on the other end of said shaft for bypassing pressure fluidfrom said source to vary the pressure with which said clutchfrictionally drives said driven member.

9. In a supercharger the combination of a casing, a driving shaftmounted in bearings in said casin having a driver ear intermediate theen 5 thereof, an impel er plate driven by said shaft and coaxiallyarranged with res ect thereto at one end, means for introducing ressurefluid to a bore extending longitudinally of said shaft, and means.

between one end of said shaft and the impeller for providing adetachable driving connection therebetween, comprising an expansiblefluid pressure metal bellows enclosing the 0 en end of said shaft, adriving plate rigi on said shaft and affixed to one end of said bellows,a second driving plate aflixed to the other end of said bellows andadapted toenga e and frictionally drive said impeller, an means forcontrolling the pressure of the fluid to vary the pressure with whichsaid second drivlng plate frictionally drives said impeller.

10. In a superchar'er the combination of a casing, a driving s aftmounted in bearings in said casing having a driver gear intermediate theends thereof, an im eller plate driven by said shaft and coaxial yarranged with respect thereto' at one end, means for introducingpressure fluid to a bore extending longitudinall of said shaft, andmeans between one an of said shaft and the impeller for roviding adetachable driving. connection t erebetween, comprising an expansiblefluid pressure metal bellows enclosing the open end of said shaft, a

driving plate rigid on said shaft and affixed to one end of saidbellows, a second drivin plate splined to said shaft affixed to theother end of said bellows and ada ted to engage and frictionally drivesai impeller, an means for controlling the pressure of the fluid to varythe pressure with which said second driving plate frictionally drivessaid impeller, comprising a relief port provided in the opposite end ofsaid shaft for bypassing pressure fluid from said shaft, and means inthe nature of inertia weights given angular deflection from a normaposition coaxial with said shaft in the sudden acceleration ordeceleration thereof for controllin said port.

n testimony whereof I aflix my signature.

DAVID DUNWOODIE.

